In the field of liquid crystal display devices, lateral electric field schemes such as IPS (in-plane switching) and FFS (fringe field switching) have been receiving attention in recent years. Among other things, these schemes are advantageous in that the direction of the electric field applied to the liquid crystal is generally parallel to the substrate surface, which makes it possible to improve visual characteristics more than with a TN (twisted nematic) display or the like. In these liquid crystal display devices using a lateral electric field scheme, liquid crystal is held between a pair of substrates that are arranged facing each other, and a pair of electrodes are disposed on one of the substrates, the TFT substrate, separated by an insulating film, with the electric field for driving the liquid crystal being generated between this pair of electrodes. Accordingly, the normal configuration is for the other substrate, the color filter substrate, not to have an electrode (opposite electrode) for driving the liquid crystal, which contrasts with TN schemes and the like.
Among the liquid crystal display devices using a lateral electric field scheme, in IPS the pair of electrodes arranged on the TFT substrate do not overlap in a plan view, whereas in FFS the pair of electrodes do overlap in a plan view. In FFS, the pair of electrodes is arranged above/below one another with an insulating film therebetween, with one of the electrodes being a pixel electrode and the other being a common electrode. The liquid crystal display device can be operated regardless of whether the electrode disposed lower among the pair of electrodes is the pixel electrode or common electrode. Patent Document 1 below, for example, discloses an FFS liquid crystal display panel in which, among the pair of electrodes, the pixel electrode is disposed lower and the common electrode is disposed higher.